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United States Patent |
6,024,326
|
Godfrey
,   et al.
|
February 15, 2000
|
Water-impact release mechanism
Abstract
A water-impact release mechanism has a hub with a first sleeve coupled
thto. The first sleeve has a plurality of circumferentially distributed
holes therein. A spring assembly, coupled to the hub, extends into the
first sleeve. In a relaxed state, the spring assembly obstructs the holes
while, in a compressed state, the spring assembly does not obstruct the
holes. A second sleeve, concentric with the first sleeve, is elastically
coupled to the hub and biased away therefrom. The second sleeve has an
inwardly-facing annular groove. A ball resides in each of the holes and is
large enough to extend beyond the confines of its hole. When the bias of
the second sleeve is overcome, the annular groove aligns with the holes in
the first sleeve thereby allowing the radial outward movement of the
balls. A plate, coupled to the second sleeve, extends radially outward
therefrom to define a water-impact surface. Water-impact forces impinging
on the plate cause the bias of the second sleeve to be overcome such that
the second sleeve abuts the hub.
Inventors:
|
Godfrey; Daniel M. (North Kingstown, RI);
Berlam; Gary R. (Warwick, RI)
|
Assignee:
|
The United States of America as represented by the Secretary of the Navy (Washington, DC)
|
Appl. No.:
|
062566 |
Filed:
|
April 20, 1998 |
Current U.S. Class: |
244/151B; 244/138R; 244/139 |
Intern'l Class: |
B64D 001/02 |
Field of Search: |
244/138 R,139,151 B,137.3,137.4
114/22
74/527
|
References Cited
U.S. Patent Documents
2778308 | Jan., 1957 | Fogal et al. | 244/151.
|
2880687 | Apr., 1959 | Kilvert | 114/22.
|
3066632 | Dec., 1962 | Bemis | 114/22.
|
4132147 | Jan., 1979 | Contaldo | 244/137.
|
4592524 | Jun., 1986 | Nohern et al. | 244/138.
|
Primary Examiner: Poon; Peter M.
Assistant Examiner: Ducker, Jr.; Charles R
Attorney, Agent or Firm: McGowan; Michael J., Kasischke; James M., Lall; Prithvi C.
Goverment Interests
STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the
Government of the United States of America for Governmental purposes
without the payment of any royalties thereon or therefor.
Claims
What is claimed is:
1. A water-impact release mechanism, comprising:
a hub;
a first sleeve coupled to and extending from said hub, said first sleeve
defining a plurality of holes distributed about the circumference of said
first sleeve and extending therethrough;
a spring assembly coupled to said hub and extending into said first sleeve
wherein, in a relaxed state, said spring assembly obstructs said plurality
of holes from within said first sleeve and wherein, in a compressed state,
said spring assembly does not obstruct said plurality of holes from within
said first sleeve;
a second sleeve concentric with said first sleeve extending from said hub,
said second sleeve elastically coupled to said hub and having a bias away
therefrom wherein said second sleeve can move axially about said first
sleeve, said second sleeve having an inwardly-facing annular groove formed
therein in a plane perpendicular to a longitudinal axis of said second
sleeve wherein, when said bias is overcome such that said second sleeve
abuts said hub, said annular groove is aligned with said plurality of
holes;
a plate coupled to said second sleeve and extending radially outward
therefrom to define a water-impact surface, wherein water-impact forces
impinging on said plate cause said bias to be overcome such that said
second sleeve abuts said hub; and
a plurality of balls, each said ball residing in a corresponding one of
said plurality of holes, each of said plurality of balls being large
enough to extend beyond the confines of said corresponding one of said
plurality of holes, wherein said plurality of balls are pressed into
engagement with a device to be released when the device is inserted into
said first sleeve to compress said spring assembly to said compressed
state and when said second sleeve is in a position such that said annular
groove is misaligned with respect to said plurality of holes.
2. A mechanism as in claim 1 further comprising a frangible retainer
coupled to said second sleeve for fixing said second sleeve in said
position where said annular groove is misaligned with respect to said
plurality of holes, wherein said frangible retainer releases said second
sleeve when said water-impact forces impinge on said plate such that said
bias is overcome and said second sleeve abuts said hub.
3. A mechanism as in claim 2 wherein said frangible retainer passes through
a wall of said second sleeve and at least partially into a wall of said
first sleeve.
4. A mechanism as in claim 1 further comprising vibration absorbing
material interposed between a portion of said first sleeve and a portion
of said second sleeve.
5. A mechanism as in claim 1 wherein said first sleeve and said second
sleeve are indexed to one another for preventing relative rotation
therebetween.
6. A mechanism as in claim 1 wherein said annular groove is v-shaped in
cross section.
7. A water-impact release mechanism for coupling an air-stabilizer to the
aft end of a payload that has been deployed in air over a body of water
into which said payload will fall, the aft end of said payload terminating
in a hitching ball having a plurality of dimples distributed about the
periphery thereof in a plane perpendicular to a longitudinal axis of said
payload, said mechanism comprising:
a hub having a plurality of spokes serving as attachment points for said
air-stabilizer;
a first sleeve coupled to and extending from said hub, said first sleeve
defining a plurality of holes distributed about the circumference of said
first sleeve and extending therethrough;
a first spring coupled on one end thereof to said hub and extending into
said first sleeve;
a cupped plate coupled to another end of said first spring and
substantially spanning the inside diameter of said first sleeve wherein,
when said first spring is in a relaxed state, said cupped plate obstructs
said plurality of holes from within said first sleeve and wherein, when
said first spring is in a compressed state, said cupped plate does not
obstruct said plurality of holes from within said first sleeve;
a second sleeve concentric with said first sleeve extending from said hub;
a second spring coupled on one end thereof to said hub and having a bias
away therefrom, said second spring coupled on another end thereof to said
second sleeve wherein said second sleeve can move axially about said first
sleeve with movement of said second spring;
said second sleeve having an inwardly-facing annular groove formed therein
in a plane perpendicular to a longitudinal axis of said second sleeve
wherein, when said bias is overcome such that said second sleeve abuts
said hub, said annular groove is aligned with said plurality of holes;
an impact plate coupled to said second sleeve and extending radially
outward therefrom to define a water-impact surface, wherein water-impact
forces impinging on said impact plate cause said bias to be overcome such
that said second sleeve abuts said hub; and
a plurality of balls, each said ball residing in a corresponding one of
said plurality of holes, each of said plurality of balls being large
enough to extend beyond the confines of said corresponding one of said
plurality of holes, wherein each of said plurality of balls is pressed
into engagement with one of said dimples of said hitching ball when said
hitching ball is inserted into said first sleeve and pressed into said
cupped plate to compress said first spring to said compressed state, and
when said second sleeve is in a position such that said annular groove is
misaligned with respect to said plurality of holes.
8. A mechanism as in claim 7 further comprising a frangible retainer
coupled to said second sleeve for fixing said second sleeve in said
position where said annular groove is misaligned with respect to said
plurality of holes, wherein said frangible retainer releases said second
sleeve when said water-impact forces impinge on said plate such that said
bias is overcome and said second sleeve abuts said hub.
9. A mechanism as in claim 8 wherein said frangible retainer is a shear pin
passing through a wall of said second sleeve and at least partially into a
wall of said first sleeve, wherein said shear pin fractures when said
impact plate is subjected to said water-impact forces.
10. A mechanism as in claim 7 further comprising at least one vibration
absorbing o-ring interposed between a portion of said first sleeve and a
portion of said second sleeve.
11. A mechanism as in claim 7 wherein said first sleeve and said second
sleeve are indexed to one another for preventing relative rotation
therebetween.
12. A mechanism as in claim 7 wherein each of said plurality of balls is
sized to contact the entire surface area of one of said dimples when said
plurality of balls are pressed into engagement with said dimples.
13. A mechanism as in claim 7 wherein said annular groove is v-shaped in
cross section.
Description
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates generally to release mechanisms, and more
particularly to a water-impact release mechanism used to couple a
deceleration device, e.g., a parachute, to the aft end of an air-deployed
device, e.g., a torpedo.
(2) Description of the Prior Art
In some Navy applications, torpedoes having air stabilizing devices (e.g.,
a parachute) are launched from an aerial platform (e.g., helicopter,
airplane, etc.). The use of an air stabilizing device reduces the velocity
upon water impact in order to prevent damage to the torpedo's structure or
control systems. The air stabilizing device is generally coupled to the
aft end of the torpedo by means of a release mechanism that causes the air
stabilizing device to separate from the torpedo when it strikes the water.
More specifically, a tail nut (i.e., similar to a hitching ball) generally
extends from the aft end of the torpedo for cooperation with the release
mechanism.
A variety of release mechanisms have been designed and used by the Navy.
One type of release mechanism is disclosed in U.S. Pat. No. 2,880,687
where the aft end of the torpedo employs concentric sleeves to position
and press a plurality of balls into engagement with a shaped plug mounted
on the air stabilizing device. At impact with the water, deceleration of
the torpedo brings about inertial movement of one of the sleeves such that
the balls are allowed to disengage from the shaped plug. However, the
inertial force is opposite that of the friction force generated by the
drag force of the air stabilizing device. Accordingly, if the inertial
force does not overcome the drag force sufficiently, the release mechanism
can fail causing the torpedo to drag the air stabilizing device into the
water.
SUMMARY OF THE INVENTION
Accordingly it is an object of the present invention to provide a
water-impact release mechanism.
Another object of the present invention is to provide a water-impact
release mechanism that is a reliable in its release operation.
Still another object of the present invention is to provide a water-impact
release mechanism that securely retains a payload until time of release.
Yet another object of the present invention is to provide a water-impact
release mechanism that is simple to use.
Other objects and advantages of the present invention will become more
obvious hereinafter in the specification and drawings.
In accordance with the present invention, a water-impact release mechanism
has a hub with a first sleeve coupled to and extending from the hub. The
first sleeve defines a plurality of holes distributed about the
circumference thereof and extending therethrough. A spring assembly is
coupled to the hub and extends into the first sleeve. In a relaxed state,
the spring assembly obstructs the holes from within the first sleeve.
However, in a compressed state, the spring assembly does not obstruct the
holes. A second sleeve is concentric with the first sleeve and is
elastically coupled to the hub such that it has a bias away therefrom. The
second sleeve can move axially about the first sleeve. The second sleeve
has an inwardly-facing annular groove formed therein in a plane
perpendicular to a longitudinal axis of the second sleeve. A ball resides
in each of the holes in the first sleeve and is large enough to extend
beyond the confines of its hole. Each ball is pressed into engagement with
a device to be released when i) the device is inserted into the first
sleeve to compress the spring assembly to said compressed state, and ii)
the second sleeve is in a position such that the annular groove is
misaligned with respect to the holes in the first sleeve. However, when
the bias is overcome such that the second sleeve abuts the hub, the
annular groove is aligned with the holes in the first sleeve thereby
allowing the radial outward movement of the balls. A plate is coupled to
the second sleeve and extends radially outward therefrom to define a
water-impact surface. Water-impact forces impinging on the plate cause the
bias of the second sleeve to be overcome such that the second sleeve abuts
the hub.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention will become
apparent upon reference to the following description of the preferred
embodiments and to the drawings, wherein corresponding reference
characters indicate corresponding parts throughout the several views of
the drawings and wherein:
FIG. 1 is a cross-sectional view of the water-impact release mechanism
according to the present invention in its release or unlocked position;
FIG. 2 is a cross-sectional view of the release mechanism in its locked
position with the dimpled hitching ball of a payload engaged by the
release mechanism; and
FIG. 3 is a sectional view taken along line 3--3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
Referring now to the drawings, simultaneous reference will be made to FIGS.
1, 2 and 3 in order to explain the water-impact release mechanism of the
present invention which is referenced generally by numeral 10 in FIGS. 1
and 2. In the illustrated embodiment, a dimpled tail nut or hitching ball
100 is the device to be engaged and released by release mechanism 10.
Hitching ball 100 is typically attached to the aft end of a payload 110
(e.g., a torpedo) that is to be deployed in air over a body of water into
which payload 110 is to fall. By way of example, hitching ball 100 has a
plurality of spherical dimples 102 distributed about the periphery thereof
in a plane perpendicular to the longitudinal axis 104 of hitching ball 100
and payload 110. This design of hitching ball 100 is one commonly used by
the Navy.
Release mechanism 10 has a hub structure 12 which, for the illustrated
embodiment, has a plurality of spokes, (only two spokes 12A and 12B are
shown for sake of clarity,) extending radially away from the central
portion of hub structure 12. Additional spokes can be provided as needed.
Spokes 12A and 12B serve as attachment points for, in the case of the
illustrated embodiment, risers 200 extending from an air stabilizing
device (not shown) such as a parachute. The air stabilizing device
decelerates payload 110 after its air-deployment and aligns payload 110
for a vertical (or nearly vertical) entry into the water.
A sleeve 14 extends from the central portion of hub structure 12. Sleeve 14
is provided with a plurality holes, e.g., holes 14A, 14B and 14C are
shown, distributed about sleeve 14. For reasons that will become apparent
below, the number of holes 14A-14C is commensurate with the number of
dimples 102 on hitching ball 100. The center of holes 14A-14C lie in a
plane perpendicular to longitudinal axis 16 of hub structure 12 and sleeve
14, and are distributed in a pattern commensurate with dimples 102.
A spring 18 is attached on one end thereof to hub 12 and extends into
sleeve 14. Attached to the other end of spring 18 is a concave or cupped
plate 20 which serves several functions. When spring 18 is in its relaxed
state (as shown in FIG. 1) the outer edge of cupped plate 20 is aligned
with holes 14A-14C. Since cupped plate 20 substantially spans the inside
diameter of sleeve 14, holes 14A-14C are obstructed such that balls 30
cannot fall into the interior of sleeve 14 when spring 18 is relaxed. When
spring 18 is in its compressed state (as shown in FIG. 2), holes 14A-14C
are no longer obstructed by the cupped plate 20. The significance of this
will become apparent from the operational description that is to follow
the physical description of the present invention. The cupped shaped of
plate 20 also serves to properly align longitudinal axis 104 (of hitching
ball 100) and longitudinal axis 16 (of sleeve 14) when hitching ball 100
is installed in release mechanism 10.
A retainer sleeve 22 is concentric with sleeve 14 and is in sliding
engagement therewith in an axial direction. Sleeve 22 is elastically
coupled to the central portion of hub structure 12 by means of a spring
24. More specifically, spring 24 is attached on one end thereof to hub
structure 12 and on the other end thereof to sleeve 22. Spring 24 is
biased away from hub structure 12. Sleeve 22 is provided with an annular,
inwardly-facing, V-shaped channel or groove 26 in a plane perpendicular to
longitudinal axis 16. Groove 26 is positioned such that when sleeve 22 is
moved to overcome the bias in spring 24, groove 26 can be aligned with
holes 14A-14C. To assure such alignment, sleeve 22 is sized to abut hub
structure 12 (for example, at annular shoulder 12C) when groove 26 is
aligned with holes 14A-14C.
An impact or splash plate 28 is attached to or is integral with sleeve 22.
Splash plate 28 extends radially out from sleeve 22 and beyond the
confines of payload 110. In this way, splash plate 28 defines an annular
surface 28A that receives the water impact forces as payload 110 completes
its water entry. The size of the area presented by annular surface 28A is
selected such that the minimum expected impact forces (represented by the
arrows designated F.sub.i in FIG. 2) impinging on splash plate 28 are
sufficient to overcome the bias in spring 24 and cause sleeve 22 to abut
annular shoulder 12C.
As mentioned above, a ball 30 resides in each of holes 14A-14C. Each ball
30 must be large enough to extend beyond the confines of each hole 14A-14C
as defined by the wall thickness of sleeve 14. In addition, for the
illustrated embodiment, each ball 30 is sized such that it completely
contacts the entire surface area of one of dimples 102 when pressed into
engagement therewith.
In operation, hitching ball 100 must first be installed in release
mechanism 10. Just prior to such installation, release mechanism 10 is
configured as shown in FIG. 1. Specifically, spring 18 is in its relaxed
state so that cupped plate 20 is positioned in front of holes 14A-14C, and
sleeve 22 abuts hub structure 12 so that groove 26 is aligned with holes
14A-14C. As hitching ball 100 is pressed against cupped plate 20 along
longitudinal axis 16, spring 18 is compressed towards hub structure 12.
This frees balls 30 to be pressed into engagement with dimples 102. Note
that this cannot occur unless dimples 102 are properly aligned with holes
14A-14C. Balls 30 are then pressed into engagement with dimples 102 as
sleeve 22 is released. The natural bias of spring 24 causes sleeve 22 to
move away from hub structure 12 while the V-shape of groove 26 facilitates
the radially-inward pressing action of sleeve 22 on balls 30. Once
hitching ball 100 is installed, release mechanism 10 is configured as
shown in FIG. 2. Groove 26 is no longer aligned with holes 14A-14C so that
sleeve 22 maintains balls 30 in engagement with dimples 102.
To prevent unwanted axial movement of sleeve 22 that could lead to
premature release of hitching ball 100, a retainer can be used to couple
the two sleeves to one another when hitching ball 100 is installed (FIG.
2). The retainer should be frangible upon application of water-impact
forces F.sub.i on annular surface 28A so that forces F.sub.i move sleeve
22 to abut hub structure 12 as described above. One embodiment of such a
retainer is a shear pin or screw 32 (FIG. 3) that can be inserted through
the wall of sleeve 22 and at least partially into the wall of sleeve 14
when hitching ball 100 is installed. Shear pin 32 is designed to fracture
at the interface of sleeve 22 and sleeve 14 upon the application of
water-impact forces F.sub.i.
Although the present invention has been described relative to a particular
embodiment, it is not so limited. For example, relative rotation between
sleeves 22 and 14 may be prevented by indexing sleeve 22 to sleeve 14. One
way of accomplishing this is shown in FIG. 3 where a vertical notch 15 in
sleeve 14 receives an inward-facing rib or pin 23 coupled to sleeve 22.
Pin 23 can slide within notch 15 to allow for axial movement between
sleeves 14 and 22 while constraining any relative rotational movement.
Vibrational chatter between sleeves 22 and 14 can be reduced or eliminated
by the use of one (or more) o-ring 34 made of vibration damping material
(e.g., rubber) interposed between the sleeves. Still further, depending on
the shape of hitching ball 100, the inner portion of outboard end 14D of
sleeve 14 can be specially configured to both properly align hitching ball
101 upon insertion and also serve as a limit stop to prevent hitching ball
100 from being inserted too far into sleeve 14. In the illustrated
embodiment, the inner portion of end 14D is tapered to abut a
corresponding taper on hitching ball 100. Thus, it will be understood that
many additional changes in the details, materials, steps and arrangement
of parts, which have been herein described and illustrated in order to
explain the nature of the invention, may be made by those skilled in the
art within the principle and scope of the invention as expressed in the
appended claims.
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